368 Cooke and Schively on Observations on the 
corolla is long and tubular, with open mouth. The style is 
very much longer here, each stamen is much better devel- 
oped, as is also the nectary. Otherwise, the flowers are 
similar. The intermediate flowers have short tubular open 
corollas. The lengths of style and stamens are about midway 
between those of the cleistogamic and chasmogamic struc- 
tures. 
So these chasmogamic flowers are to be regarded as more 
primitive structures, persisting before the degrading influ- 
ence of parasitism had affected the plant. The intermediate 
flowers show the course taken by increasing degeneration, in 
so modifying the flower as to produce the present function- 
ing cleistogamic blooms. 
HISTOLOGY OF THE MATURE STEM. 
The aerial stem is triangular or tri-lobed in section, the 
lobes being separated by three deep grooves. These grooves 
are quite densely filled by hair outgrowths, though hairs are 
rare on the outer lobed portions of the stem. They are 
purely epidermal outgrowths, and vary much in size and in 
the number of constituting cells. Some are of eight cells, 
lying in a single row, and capped at the outer end by a trans- 
verse row of two or four cells. These multicellular hairs 
are the densest of all, containing rich cytoplasm and gran- 
ular cell contents. Other hairs are long single cells, as large 
as the entire multicellular. These are empty and vacuolated, 
with a little faintly staining cytoplasm about the wall. It 
seems likely that these are worn-out multicellular hairs in 
which the cross walls have all or partly broken down. Some 
hairs show clear cuticular caps along their outer cell walls. 
These hairs are nearly all thin-walled, with a swollen turgid 
aspect, well adapted for an absorbing function. They must 
hold back and collect the water trickling down the grooves 
in the stem, and may even take up this water and its dis- 
solved salts. 
